Laparoscopic surgery is commonly performed using trocars having septum valves and zero valves which provide instrument access across an abdominal wall and into a gas pressurized abdominal cavity. The functional requirements of such valves can be many and varied. In some embodiments the valves should be very durable even when challenged by the insertion of sharp-pointed instruments. They should be capable of accommodating a wide range of inserted instrumentation without leaking. They should be nearly friction-free so that they do not interfere with the action of the instrument. And, of course, they should not damage the inserted instruments. In addition, they should be cost-effective and user-friendly, and they should not add to the complexity of a surgical procedure.
There are presently many trocars and trocar valves that attempt to address the needs of laparoscopic surgeries. Perhaps most notable of these is the trocar structure which includes a “floating” septum seal as disclosed and claimed in U.S. Pat. No. 5,385,553. In this patent, a septum valve is disclosed with a movable attachment portion which permits the sealing orifice of the septum valve to follow the lateral movement of an inserted instrument. This movement or “float” of the septum valve is accommodated primarily in a two-dimensional plane which is disposed generally perpendicular to the axis of the trocar. As the instrument is moved laterally, the septum valve floats so that the sealing orifice remains generally round thereby maintaining a strong sealing relationship with the instrument. The floating septum allows the use of a delicate, larger bore septum since the floating orifice is not inordinately challenged or elongated as the inserted instrument is manipulated.
In comparison, a septum valve that does not float must be constructed of very durable material and provided with a very small orifice in order to maintain a gas-tight sealing relationship with the inserted instrument. The tradeoff in this case is friction and sensitivity. By floating the septum valve, laparoscopic trocars have been made more durable and sensitive.
In several existing “floating” systems, the “float” has been provided only in a lateral direction. As a result, the desirable floating characteristics are available only when the instrument is in place. This leaves even the floating valves vulnerable to instruments upon insertion. Instruments having sharp points can be particularly detrimental to the valve structure.
Elongate tubular structures of the past have not functioned in the manner of the present invention. For example, the tubular structure disclosed in U.S. Pat. No. 5,492,304 does not function to guide a seal into alignment with the instrument, but rather is provided merely to change the size of a septum valve. Similarly, the tubular structure in U.S. Pat. No. 5,820,600 does not pendulate and is not coupled to a septum valve which is disposed distally of a pivot point.
Laparoscopic surgery is an evolving modality. Significant changes in instrumentation have challenged even the best trocar valves presently in use. Accordingly, there remains a continuing need to extend the range, durability and sensitivity of trocar valves.